DESCRIPTION: (Applicant's Description) This proposal is for an investigation into the associations of diet, and interactions of diet and genetic polymorphisms, with the risk of lung cancer. Data are from 18,314 men and women enrolled in a chemoprevention trial of beta-carotene and retinol (CARET). After a mean of 7.4 years of follow up, CARET has endpoint data on almost 800 cases of lung cancer. Dietary intake was measured with a food frequency questionnaire. Serum micronutrient and genetic polymorphisms have been analyzed for 388 lung cancer cases and 753 controls. Our specific aims are: 1. To better understand the association of fruit and vegetable intake with the reduced risk of lung cancer. Fruit and vegetable intake will be measured as: (i) servings per day (total and grouped by phytochemical content), (ii) micronutrient associated with fruits and vegetables, including vitamins C and E, folate, and carotenoids, and (iii) serum carotenoids and vitamin E. 2. To examine whether the associations of fruit and vegetable intake with lung cancer risk are modified by genotypes of carcinogen metabolizing enzymes (i.e., CYP2D6, CYP2El, CYP1Al, GSTM1, GSTT1, and EH). We will conduct cohort analyses for dietary intake data and case control analyses for laboratory based studies. Although the baseline dietary data have been collected and the laboratory analyses (for serum micronutrients and genotypes) have been completed, there are no CARET investigators with expertise in nutrition science who are funded to conduct these analyses and write the associated manuscripts. Therefore, to meet the specific aims proposed above, we request support for nutritional epidemiologists, a statistician, molecular biologist, and the staff support needed to publish the findings. This work addresses important questions about the etiology and prevention of lung cancer, and can be completed with a modest amount of funding in addition to what has already been invested in this large chemoprevention trial.